Caffeine doubles miscarriage risk

Lay off the coffee, pregnant women advised

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Pregnant women have been warned to lay off the coffee after US researchers found that those who "drink two or more cups of coffee a day have twice the risk of having a miscarriage as those who avoid caffeine".

The study led by Dr De-Kun Li of Kaiser Permanente Division of Research, which appears in the American Journal of Obstetrics and Gynecology, concludes that an intake of 200 milligrams or more per day, representing two or more cups, "significantly increases the risk of miscarriage".

Li told Reuters: "There has been a lot of uncertainty about this. There was no firm advice from professional societies to say what a pregnant woman should do about caffeine intake."

He duly cautioned: "Women who are pregnant or are actively seeking to become pregnant should stop drinking coffee for three months or hopefully throughout pregnancy."

Li explained that while other studies have demonstrated a link between caffeine and miscarriage, the link had been "clouded by the fact that many pregnant women avoid caffeine because it makes them nauseated, which could skew the results".

Accordingly, Li and his team legislated for that possibility during their study of 1,063 pregnant women who were members of the Kaiser Permanente health plan in San Francisco from October 1996 to October 1998, and who "never changed their caffeine consumption during pregnancy".

The link between caffeine and misscarriage may be, according to Li, that the chemical stresses the unborn child's immature metabolism and possibly decreases blood flow in the placenta.

Dr Tracy Flanagan, director of women's health at Kaiser Permanente Northern California, backed Li's call to cut out the coffee, concluding: "So many causes of miscarriage are not controllable. This is an opportunity to do something active." ®